This invention relates to apparatus for laying fiber fleeces or the like, usually supplied from a carding machine or the like, onto a withdrawal belt moving at a predetermined speed.
In high speed apparatus for laying fiber fleeces, any sudden change in speed of the various conveyor belts in the apparatus can cause irregularities and distortions in the fleece layer. Thus, during a sudden acceleration of the conveyor belts the fleece does not follow immediately, and at high operational speeds air currents are generated which tend to raise the fleece from the belts and can lead to narrowing or stretching of the fleece at points between conveyor belts.
One of the objectives in designing apparatus for laying fiber fleeces has been to provide control means for maintaining the conveyor belts in a predetermined relationship whereby the fleece layer is maintained more uniform. In prior art apparatus each conveyor belt is frequently controlled by a separate DC motor, the DC motors enabling digital control of the speeds of the belts. This, however, requires a complex and therefore expensive control device and also requires continuous supervision by highly skilled personnel. Furthermore, the adverse affects caused by air currents are not eliminated.
Other prior art devices have been designed to decrease the high rate of acceleration. This is difficult to control, however, as the fleece is fed to the apparatus at constant speed and must be withdrawn at constant speed.
Another prior art apparatus is known in which there is a feed belt driven at a predetermined speed, a reciprocably movable main or storage car and laying car and two conveyor belts which extend partially parallel to each other between the main and layer cars. One of the conveyor belts, a main belt, passes over rollers on the main and layer cars. Three auxiliary cars are provided which are intended to effect balance of the belt speeds during laying of the fleece in a cross-over form. Also, the drive requires at these two different gears. This apparatus has the disadvantage that it is relatively expensive and complex, both in structure and with respect to the control device required to operate the apparatus.
An object of the present invention is to provide apparatus for laying fiber fleeces which has a simplified construction and reduction in the number of parts.
A further object of the invention is to provide an apparatus in which control of the synchronous running of the moving parts is simplified.